1. Field of the Invention
The present invention relates to an interference alignment method for maintaining no interference between users located in a cell in a cellular network, and dividing a desired signal and interference from other cells into different signal spaces.
2. Background Art
In recent times, the number of high-speed wireless communication such as the Internet is rapidly increasing. Therefore, many developers and companies are conducting intensive research into a variety of communication techniques capable of guaranteeing high-speed wireless communication for the next-generation wireless communication system.
Therefore, many researches for enabling a plurality of users to efficiently use resources such as time, frequency, space, etc. for communication are underway. However, the conventional technologies such as frequency division access, time division access, and code division access cannot obtain higher channel capacity for high-speed communication due to interference among many users or UEs as compared to given resources.
Therefore, there is proposed interference alignment (IA) technology for dividing a desired signal and undesired interference into different spaces and transmitting the desired signal and the undesired interference through different spaces so as to solve the problem in which it is impossible to obtain high channel capacity due to interference between users or UEs, such that theoretical development of a transmission/reception technique has been continuously achieved. The IA technology prevents throughput deterioration caused by interference without complicated error correction coding in multi-user environments of a general interference channel, and at the same time maximizes use of given resources so as to obtain a maximum degree-of-freedom, such that the IA technology can obtain a high channel capacity.
In more detail, the IA technology can almost achieve channel capacity of an interference channel under a high SNR. The IA technology has been extended not only to an interference channel but also to a cellular network, and has been intensively researched. Users (or UEs) located at another cell in a cellular network composed of two cells can arrange interference signals affecting a base station (BS) of a current cell in a specific signal space, and receive the arranged interference signals, such that many more signal spaces for users located in the current cell can be acquired. For example, assuming that each user (or each UE) transmits only one stream, the user may arrange interference signals affecting the BS of another cell within a signal space of one dimension, and receive the arranged interference signals.